Chemical and biological agents pose a real and unpredictable threat to mankind. A wide variety of synthetic chemicals, toxins and biological materials have been developed for use as warfare or terror agents. Some chemical and biological agents are readily available and could easily be prepared in large quantities. Detecting chemical and biological agents quickly and accurately at very low concentration levels is crucial to a successful defense against the use of such agents as weapons.
Chemical effluent from chemical processing plants or factories, from leakage of fuels such as rocket propellants, or from volatility of chemical tags specifically placed in medicines or explosives also needs to be detected with sensitivity either remotely or in close proximity.
Since chemical and biological agents are effective in small doses, sensitivity is a critical feature of any detection system. Complex and rapidly changing operating conditions also require a detection system to exhibit a high degree of selectivity. In other words, selectivity is needed to discriminate chemical and biological agents from other harmless materials present in the environment. Lastly, the speed in which an agent is identified is essential for determining an appropriate response to a threatening condition. Moreover, speed is an important characteristic in that the response of multiple agents can be searched for during the scan. Therefore, it is desirable to provide a detection scheme which addresses each of these technical challenges.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.